Success in a Nebraska Cornfield
A collaborative effort involving researchers from Stanford, Schlumberger and the U.S. Geological Survey successfully drilled and logged a well in the Ogallala aquifer.
Growing concerns about the availability of fresh water for agriculture and the impact of water use on ecosystems has led scientists to seek a better understanding of groundwater aquifers. One of the largest and most important aquifers in the world is the Ogallala aquifer, which stretches through parts of eight states in the central U.S. over an area of approximately 174,000 square miles. This single aquifer provides roughly 30 percent of the nation's groundwater used for irrigation.
Last November scientists from Stanford, the U.S. Geological Survey, and Schlumberger Water Services converged on a Nebraska cornfield to drill a well into the Ogallala aquifer. With funding from the National Science Foundation, the drilling was followed by acquisition of core samples and a suite of advanced geophysical logs â€“ 1D measurements of the aquifer properties every few inches, to a total depth of 500 ft. This month, the U.S. Geological Survey is back at the site, conducting aquifer tests. All of these datasets will be used to explore new ways of using geophysical measurements to characterize groundwater aquifers.
Researchers at Stanford are particularly interested in characterizing the Ogallala aquifer based on its NMR (nuclear magnetic resonance) properties. NMR logging techniques have been used in oil and gas applications for decades to estimate key properties of oil reservoirs such as permeability, a property which describes how easily fluids will flow through a geologic formation. This current research aims to extend NMR techniques to groundwater applications using a variety of NMR measurements. In their study, researchers will utilize laboratory NMR measurements made on the cored samples from the well, NMR logging data collected directly at the well, and non-invasive measurements acquired using a new surface-based NMR technology. The goal is to integrate these complementary data in order to better characterize the permeability of the Ogallala and the quantity of water stored there. Understanding these properties is vital to predicting how the aquifers will respond to use over time, and help determine how best to manage this important groundwater resource.